Newberry Volcano is the largest volcano in the Cascades volcanic arc and covers an area the size of Rhode Island (about 3100 km2 or 1200 mi2). Unlike familiar cone-shaped Cascades volcanoes, Newberry was built into the shape of a broad shield by repeated eruptions over the past 400,000 years. Throughout its eruptive history, Newberry has produced ash and tephra, pyroclastic flows, and lava flows that range in composition from basalt to rhyolite. About 75,000 years ago a major explosive eruption and collapse event created a large volcanic depression at its summit that now hosts two caldera lakes. Newberry last erupted about 1,300 years ago, and present-day hot springs and geologically young lava flows indicate that it is still an active volcano.